The present invention relates generally to a disposable flashlight and more specifically to a disposable fluid-activated flashlight suited to normal usage as well as emergency situations.
Disposable flashlights have been in use for years. Examples of such devices are described in U.S. Pat. Nos. 3,796,869, 4,122,510, 4,429,352 and 4,939,626. Typically, the flashlight has a housing, battery, bulb, and switch. The bulb is lit via the switch, located on the housing of the flashlight, which completes the electrical circuit and allows the current from the battery to energize and illuminate the bulb.
A significant problem with the conventional flashlights is their unreliability in moisture and wet conditions. The circuit may be shorted and the flashlight rendered inoperable. During storage, the batteries may be weakened due to current leakage, and the switch mechanisms corroded. Such batteries are unsuited for use in emergency lighting, particularly where their use involves exposure to high humidity environments or water, as in search and rescue missions.
U.S. Pat. Nos. 5,237,491, 5,311,100, and 5,340,662 describe water-activated batteries developed for emergency operations encountering high humidity or water. These types of devices, available from sources such as A.C.R. Electronics Inc., Florida, are bulky and expensive to manufacture.